Note: Javascript is disabled or is not supported by your browser. For this reason, some items on this page will be unavailable. For more information about this message, please visit this page: About CDC.gov.

This report describes an observational approach for assessing postural stress of the trunk and upper limbs that is intended to improve risk analysis for prevention of musculoskeletal disorders. The approach is supported by several recent research studies. These studies have evaluated how much time it takes observers to classify specific trunk and upper limb postures, how frequently observers are likely to make posture classification errors, and the magnitude of these errors. The frequency and magnitude of posture classification errors depend on how many categories (levels) are available from which to classify the specific posture. Recent studies suggest that optimal posture analysis performance is obtained by partitioning trunk flexion range of motion into 4 categories of 30 degrees increments; trunk lateral bend into 3 categories of 15 degrees increments; shoulder flexion into 5 categories of 30 degrees; shoulder abduction into 5 categories of 30 degrees; and elbow flexion into 4 categories of 30 degrees. These categories are suggested because they optimize how rapidly and effectively analysts can visually judge posture. This report also presents more general guidelines for the video recording of posture and for the posture analysis process. Guidelines for video recording address such factors as camera position, field of view, lighting, and duration of recording. Guidelines for posture analysis address enhancements such as the benefits of digital video, computer software, training, and use of visual reference and perspective cues. Information in this report can assist health/safety, ergonomics, and risk management/loss control practitioners who conduct job/worksite assessments of lifting, pushing, pulling, carrying, and/or manual handling risk factors.